Cognitive deficits in schizophrenia account for a significant proportion of the disability and dysfunction that this illness confers on Veterans. We currently do not have effective treatments for these symptoms. This proposal will test the efficacy of repetitive transcranial stimulation (rTMS) on treating cognitive deficits in schizophrenia using a randomized double-blind, parallel groups design in which half the participants with schizophrenia will be randomly assigned to receive active rTMS to the dorsolateral prefrontal cortex (DLPFC) and the other half to receive sham rTMS. Comparisons of cognitive performance before and after treatment will determine if rTMS is effective in treating cognitive deficits. In addition to testing rTMS efficacy, we will also determine whether the remediation of cognitive deficits is mediated by improving gamma band oscillation. Gamma oscillations is a electroencephalogram (EEG) measure of the coordinated neural activity underlying cognition. It is that thought a core pathophysiologic mechanism for cognitive deficits in schizophrenia involves impaired gamma oscillations. We will measure frontal gamma levels using EEG before and after rTMS to determine if rTMS remediates gamma deficits and whether it correlates with the magnitude of improvements in cognitive performance with rTMS. The successful completion of this grant will provide important information on the efficacy of a new promising treatment for cognitive deficits in schizophrenia. Furthermore, it will validate EEG gamma measurements as a predictive biomarker of therapeutic response to rTMS.